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Ellenbergerite
A valid IMA mineral species
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About Ellenbergerite
François T. V. Ellenberger
Formula:
Mg6(Mg,Ti,Zr,â»)2(Al,Mg)6Si8O28(OH)10
Colour:
Purple to lilac; some individuals exhibit smoky or pink cores.
Lustre:
Vitreous
Hardness:
6½
Specific Gravity:
3.15 - 3.22
Crystal System:
Hexagonal
Name:
Named by Chopin et al. in 1986 in honor of François Théodore Victor Ellenberger (5 May 1915, Lealui, Northern Rhodesia (now Zambia) - 11 January 2000, Bures-sur-Yvette, France), Professor of Structural Geology, University of the Sorbonne, Paris, for his work in the western Alps. In 1976 he created the French Committee of History of Geology (COFRHIGEO) and published 'Histoire de la Géologie' in two volumes (1988 and 1994).
The Type Locality is indicated as Case Parigi (better Case Paris as known "in loco") but the classic outcrop is very near to Case Ramello.
Closely related to phosphoellenbergerite. Compare 'ellenbergerite-(PO4)'.
Closely related to phosphoellenbergerite. Compare 'ellenbergerite-(PO4)'.
Unique Identifiers
Mindat ID:
1366
Long-form identifier:
mindat:1:1:1366:2
Similar Names
| Ellenbergerite-(PO4) | (Mg,◻)2(Mg,Al)12(SiO3OH)6(PO3OH)(OH)6 |
IMA Classification of Ellenbergerite
Approved
IMA Formula:
Mg6(Mg,Ti4+,Zr4+,â»)2(Al,Mg)6Si8O28(OH)10
Approval year:
1984
First published:
1985
Type description reference:
Klaska, R. (1985) Ellen- bergerit, ein neues Hochdruck-Mg-AI-(Ti,Zr)-Silikat mit flĂ€chenverknĂŒpfen- den Oktaedern [Ellenbergerite, a new high-pressure Mg-Al-(Ti,Zr) silicate with face-sharing octahedra], in Referate der 24. Diskussionstagung der Arbeitsgemeinschaft Kristallographie der Deutschen Mineralogischen Gesellschaft, der Deutschen Physikalischen Gesellschaft, der Gesellschaft Deutscher Chemiker und der 16. Jahrestagung der Deutschen Gesellschaft fĂŒr Kristallwachstum und KristallzĂŒchtung (DGKK) zusammen mit der Kontaktgroep Kristalgroei Nederland (KKN), 19. bis 22. MĂ€rz 1985 in Köln. Zeitschrift fĂŒr Kristallographie - Crystalline Materials, 170 (1). 93-95 doi:10.1524/zkri.1985.170.14.1
Classification of Ellenbergerite
9.AF.80
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
52.4.10.1
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
4 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] and/or >[6] coordination
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
4 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] and/or >[6] coordination
16.14.10
16 : Silicates Containing Aluminum and other Metals
14 : Aluminosilicates of Ti, Zr, Sn and Pb
16 : Silicates Containing Aluminum and other Metals
14 : Aluminosilicates of Ti, Zr, Sn and Pb
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Ell | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Ell | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185â187 doi:10.2138/am.2010.3371 |
| Ell | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Pronunciation of Ellenbergerite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Ellenbergerite
Vitreous
Transparency:
Transparent
Colour:
Purple to lilac; some individuals exhibit smoky or pink cores.
Hardness:
6½ on Mohs scale
Tenacity:
Brittle
Density:
3.15 - 3.22 g/cm3 (Measured) 3.13(4) g/cm3 (Calculated)
Optical Data of Ellenbergerite
Type:
Uniaxial (-)
RI values:
nω = 1.6553 - 1.6789 nε = 1.6538 - 1.6697
Max. Birefringence:
δ = 0.002 - 0.009
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 ”m thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 ”m thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Strong
Comments:
O = colorless; E = colorless to deep lilac
Chemistry of Ellenbergerite
Mindat Formula:
Mg6(Mg,Ti,Zr,â»)2(Al,Mg)6Si8O28(OH)10
Element Weights:
Common Impurities:
Zr,Fe,P
Chemical Analysis
Oxide wt%:
| 1 | 2 | |
|---|---|---|
| SiO2 | 31.19 % | 39.29 % |
| P2O5 | 11.32 % | 0.69 % |
| TiO2 | 0.34 % | 2.36 % |
| ZrO2 | 1.44 % | |
| Al2O3 | 19.00 % | 24.28 % |
| FeO | 0.50 % | 0.50 % |
| MnO | 0.03 % | 0.06 % |
| MgO | 27.16 % | 22.12 % |
| CaO | 0.06 % | 0.02 % |
| Na2O | 0.00 % | 0.00 % |
| K2O | 0.01 % | 0.00 % |
| Total: | 89.61 % | 90.76 % |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Case Parigi, Martiniana Po, Cuneo Province, Piedmont, Italy | Sample taken from an inclusion in the inner portion of a pyrope megacryst from a coesite-phengite-pyrope whiteschist. The sample is intermediate in composition between ellenbergerite and phosphoellenbergerite. Mineral analyses were performed by means of the Cameca electron microprobe (CAMEBAX) , using a wavelength-dispersive technique with PAP correction acceleration voltage 15 kV, beam current 15 nA, measuring time 20 s). | |
| 2 | " " | Sample taken from an inclusion in the outer portion of a pyrope megacryst from a coesite-phengite-pyrope whiteschist. Mineral analyses were performed by means of the Cameca electron microprobe (CAMEBAX) , using a wavelength-dispersive technique with PAP correction acceleration voltage 15 kV, beam current 15 nA, measuring time 20 s). |
Crystallography of Ellenbergerite
Crystal System:
Hexagonal
Class (H-M):
6 - Pyramidal
Space Group:
P63
Cell Parameters:
a = 12.255(8) Å, c = 4.932(4) Å
Ratio:
a:c = 1 : 0.402
Unit Cell V:
641.48 Ă
Âł (Calculated from Unit Cell)
Z:
1
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
Case Parigi, Martiniana Po, Cuneo Province, Piedmont, Italy